The following patents comprise the closest known prior art:
U.S. Pat. No. 412,195 PA1 U.S. Pat. No. 3,967,326 PA1 U.S. Pat. No. 4,052,759 PA1 U.S. Pat. No. 4,059,289
As shown in the references enumerated above, it is known in the prior art to join a drain and a waste discharge pipe by means of a resilient gasket which effects a leak-proof seal therebetween. Also, prior art shoows various means for compressing the gasket longitudinally to effect a radial expansion of the gasket so that the seal between the drain and the pipe is formed.
Generally speaking, the means for compressing the sealing gasket comprises threaded members which are secured to portions of the drain body and tightened to effect the longitudinal compression of the gasket. Often, the threaded members, such as screws or bolts, must be secured in tapped holes which are accessible only from the underside of the drain assembly. Gaining access to the underside of the drain may be extremely difficult, especially when the drain has been installed in the floor or bottom panel of a shower installation.
In other drain constructions of this type the threaded members must be introduced through narrow holes and secured in tapped holes at the lower end of the drain assembly. In this circumstance there is no means to guide the threaded member into the tapped hole, and the assembly of the threaded members in the tapped holes is attempted by reiteration and accomplished by chance. A great deal of time and labor is often wasted in assembling such devices.